Published European Patent Application No. 0,034,871 disclosed that esters of alkanoic acids can be prepared via rearrangement of .alpha.-haloketals in the presence of a Lewis acid such as a zinc salt. The process is described therein in terms of the preparation of esters of a variety of useful alkanoic acids.
General precedents for the transformation of .alpha.-haloketones to esters are published, e.g., in the following literature.
Treatment of .alpha.-bromoisobutyrophenone with silver nitrate in refluxing ethanol was reported to give a 40% yield of .alpha.,.alpha.-dimethylphenylacetic acid: A. C. Cope and E. S. Graham, J. Amer. Chem. Soc., 73, 4702 (1951), and D. J. Paslo and J. P. Sevenair, J. Amer. Chem. Soc., 93, 711 (1970). A very recent modification using silver (I) on an .alpha.-haloketone was reported by C. Giordano, et al., Tetrahedron Letters, 1385 (1982). Also, .alpha.-halocyclobutanone ketals are known to thermally rearrange to cyclopropanecarboxylates, J. Salaun and J. M. Conia, Tetrahedron Letters (1968), p. 4545. However, the use of silver salt catalysts dictates against the commercial use of such chemistry for the production of arylalkanoic acids and that prior art does not disclose procedures for preparing high yields of the desired ester intermediates. Process research studies continue to discover more efficient and less costly methods to prepare a variety of commercially significant arylalkanoic acids which have varied practical uses.